content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * -----------------------------
   * DefaultKeyedValueDataset.java
   * -----------------------------
   * (C) Copyright 2003-2012, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 27-Mar-2003 : Version 1 (DG);
   * 18-Aug-2003 : Implemented Cloneable (DG);
   * 17-Jun-2012 : Removed JCommon dependencies (DG);
   *
   */
  
  package org.jfree.data.general;
  
  import java.io.Serializable;
  
  import org.jfree.chart.util.ObjectUtilities;
  import org.jfree.data.DefaultKeyedValue;
  import org.jfree.data.KeyedValue;
  
  /**
   * A default implementation of the {@link KeyedValueDataset} interface.
   */
  public class DefaultKeyedValueDataset extends AbstractDataset
          implements KeyedValueDataset, Serializable {
  
      /** For serialization. */
      private static final long serialVersionUID = -8149484339560406750L;
  
      /** Storage for the data. */
      private KeyedValue data;
  
      /**
       * Constructs a new dataset, initially empty.
       */
      public DefaultKeyedValueDataset() {
          this(null);
      }
  
      /**
       * Creates a new dataset with the specified initial value.
       *
       * @param key  the key.
       * @param value  the value (<code>null</code> permitted).
       */
      public DefaultKeyedValueDataset(Comparable key, Number value) {
          this(new DefaultKeyedValue(key, value));
      }
  
      /**
       * Creates a new dataset that uses the data from a {@link KeyedValue}
       * instance.
       *
       * @param data  the data (<code>null</code> permitted).
       */
      public DefaultKeyedValueDataset(KeyedValue data) {
          this.data = data;
      }
  
      /**
       * Returns the key associated with the value, or <code>null</code> if the
       * dataset has no data item.
       *
       * @return The key.
       */
      @Override
      public Comparable getKey() {
          Comparable result = null;
          if (this.data != null) {
              result = this.data.getKey();
          }
          return result;
      }
  
      /**
       * Returns the value.
       *
       * @return The value (possibly <code>null</code>).
       */
      @Override
      public Number getValue() {
          Number result = null;
          if (this.data != null) {
              result = this.data.getValue();
          }
          return result;
      }
  
      /**
       * Updates the value.
       *
       * @param value  the new value (<code>null</code> permitted).
       */
      public void updateValue(Number value) {
          if (this.data == null) {
              throw new RuntimeException("updateValue: can't update null.");
          }
          setValue(this.data.getKey(), value);
      }
  
      /**
       * Sets the value for the dataset and sends a {@link DatasetChangeEvent} to
       * all registered listeners.
       *
       * @param key  the key.
       * @param value  the value (<code>null</code> permitted).
       */
      public void setValue(Comparable key, Number value) {
          this.data = new DefaultKeyedValue(key, value);
          notifyListeners(new DatasetChangeEvent(this, this));
      }
  
      /**
       * Tests this dataset for equality with an arbitrary object.
       *
       * @param obj  the object (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          if (!(obj instanceof KeyedValueDataset)) {
              return false;
          }
          KeyedValueDataset that = (KeyedValueDataset) obj;
          if (this.data == null) {
              if (that.getKey() != null || that.getValue() != null) {
                  return false;
              }
              return true;
          }
          if (!ObjectUtilities.equal(this.data.getKey(), that.getKey())) {
              return false;
          }
          if (!ObjectUtilities.equal(this.data.getValue(), that.getValue())) {
              return false;
          }
          return true;
      }
  
      /**
       * Returns a hash code.
       *
       * @return A hash code.
       */
      @Override
      public int hashCode() {
          return (this.data != null ? this.data.hashCode() : 0);
      }
  
      /**
       * Creates a clone of the dataset.
       *
       * @return A clone.
       *
       * @throws CloneNotSupportedException This class will not throw this
       *         exception, but subclasses (if any) might.
       */
      @Override
      public Object clone() throws CloneNotSupportedException {
          DefaultKeyedValueDataset clone
                  = (DefaultKeyedValueDataset) super.clone();
          return clone;
      }
  
  }
  